I was recently reading an article about Michelin looking to return to F1 on their terms. One of the statements they made was. "we want to see F1 adopt 18" wheels because they will appeal to the younger generation.
While I must admit I am impressed with the performance the teams get out of 13" rims, they do look a little bulky. but at the same time I dont think after the 2005 debacle Michelin should think they are in a position to dictate a possible return.